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Old 07-16-2010, 07:54 PM   #16
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Yes when counting ports you don't count the exhaust port or any bypass ports. Not sure who made the rules.

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Old 07-17-2010, 04:07 AM   #17
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A quote from Ron Paris:



More is not indicative of being better. If more ports were the only solution to more power, all engines would have maximum number of ports. Simply put, there is only so much room for ports in any given displacement engine. Some engines with twice the ports can have less total port area. This is not good or bad - it is just different. Every thing is a combination of many variables. Some of the most powerful engines I have built were three ports! We top qualified the world championships in Holland with a three port engine wile many of the competitors were using 5, 6, 7 and even 8 port engines and we had the fastest top speeds displayed on the board. It is true in most cases that within any brand of engine their power ratings go up with the amount of ports, but this is due to more than just the quantity of ports. Generally there are many other components in the engine that have more refined or modified parts than those with less ports, complementing the combination. You can only compare the quantity of ports between engines of the same manufacture. They all have their own combinations. In other words, brand As 17 port may or may not run equal to brand Bs 29 port.
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Old 07-17-2010, 04:28 AM   #18
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Ron Paris was Born August 5, 1950, and has been in R/C racing for over 25 years. When one thinks of 1/8th scale gas car racing, Ron Paris' name immediatly comes to mind. Ron's abilities to get the most out of miniture gas engines has won his racing team numerous titles. Back when Ron was driving, he was the Top Qualifier at the 1st CRP Challenge and West Coast Championships. He also won both the 2WD and 4WD Southern California Series in the Expert Division before acknowledging the fact that he was more valuable in preparing motors and cars for other racers. Drivers like Mike Swauger, Curtis Hustings, Cliff Lett, Tony Neisinger, and Butch Kloeber have depended on Ron's mystical motor skills.
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Old 07-17-2010, 12:08 PM   #19
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Alot of people play with there clutch and springs to help the engine run good. with the right clutch setup you can get 5 and even 7 port engines to rip on the bottom. You can also play with pipes. I have 5 port motors that will kill any 3 port engine I have had on the low end. The V-spec is the best 3 port engine I have ever run, the new Alpha and Werks 5 ports rip low - high and Tebo won nats with a 7 port w/ 1.1 springs because of the Altitude it worked for him. This is just my opinion. I am running a 5 port Extech now and it has great power all over the powerband. I ran a full mod Werks B3 with Novarossi carb and it felt the same, all I want now is killer fuel mileage and decent power and I am happy regardless of the number of ports.
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Old 07-17-2010, 11:42 PM   #20
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The advantage of more ports is the fact that it allows to have more control over the timing of the motor. They can have the ports at higher or lower positions in the cylinder to control how the air enters the engine.

A 3 port engine has one port in the middle, two on the side, the once in the middle is larger and higher, the other two are smaller ports lower in the cylinder. 5 ports, they will have one in the middle high, two that are slightly lower, and the other two even lower than that. & ports are the same other than they have 2 small notched ports between the "low" and "middle" sets of ports.

This allows how to tine the "scavaging effect" of the air moving from the bottom side of the piston to the top.
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Old 07-18-2010, 01:56 AM   #21
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There's no way to "dumb down" the discussion of the number of ports and their effect on performance. There's no universal "three ports are going to have more power here," or "seven ports are stronger here or there." Ports, regardless of their number can have a certain amount of volume, flow capacity, and timing. The manner in which the aforementioned work in conjunction with many other aspects of other engine components, is what makes the difference about how the engine runs, the least of which is the number of ports. Additional ports have been used in the past to manipulate how the air/fuel mixture enters the combustion chamber in a attempt to produce more power and efficiency by concentrating the fresh air/fuel mixture around the glow plug. Added ports have also been used to direct the fresh air/fuel mixture into the cylinder in a manner that minimizes the amount lost through the open exhaust port. I've seen up to 11-port engines, but most engine manufacturers figured out years ago that such a high number of ports doesn't do much more than increase the price of the engine.

Bottom line - make absolutely no assumptions about engine performance based on the number of ports - it will tell you NOTHING.
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Old 07-18-2010, 04:00 AM   #22
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If you take a clear look to the Novarossi onroad engines and how they perform then you have from low price up to the most expensive:

- 3 port basic -> slow
- 5 port basic -> a bit faster
- 7 port basic -> looks like something
- 7 ports competition -> competive
- 9 ports -> for most the one to have
- 9 ports tuned -> a screamer

Most people do only compare these engines on a track and see the differences and choose their options within their price range and mostly the basic line falls off.
Once I did fit a basic 3-port P/S set into the housing of an old NovaMega EVO5 competition engine. Not much modification was needed, the intakes were as good as the same but only the exhaust was raised and widened to look more like the original EVO5 exhaust and some teardrops on the intakes were made.
The engine did run very good after testing some exhausts and did even outperform a Mega ZX21-R DS2. The guy running the ZX21 did not believe it was a 3-port engine so I did take off the head and showed him, he was stunned.

The picture most people have about the ports is only made by how the manufacturers show us their products. The real big differences between those engines are how they are configured with the timings of ports and crankshaft.

The only problem you can face by tunning up a low performance engine up to a competive engine is the lifespan and strength of the materials, the rod and piston are mostly made from cheaper and less strength materials as also the crank is less hardened. For a part this is also making the differences in the prices, not only the materials but also the production costs
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Old 07-18-2010, 05:31 AM   #23
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Originally Posted by dreaux View Post
But there is definitley 4 holes but only 3 ports.
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